[OP.6A.05] NOCTURNAL BLOOD PRESSURE DECLINE BASED ON DIFFERENT TIME INTERVALS AND LONG-TERM CARDIOVASCULAR RISK: THE OHASAMA STUDY. (September 2017)

• Record Type: Journal Article
• Authors: Satoh, M.; Asayama, K.; Kikuya, M.; Inoue, R.; Tsubota-utsugi, M.; Obara, T.; Murakami, K.; Matsuda, A.; Murakami, T.; Nomura, K.; Metoki, H.; Imai, Y.; Ohkubo, T.
• Is Part Of: Journal of hypertension. Volume 35(2017)Supplement 2
• Publication Date: 2017-09
• Subjects: Hypertension -- Periodicals; Hypertension -- Periodicals; 616.132005
• DOI: 10.1097/01.hjh.0000523123.24288.66
• Languages: English
• ISSNs: 1473-5598

Abstract

Abstract : Objective: A diminished nocturnal decline in blood pressure (BP) represents a risk factor for cardiovascular disease. To define daytime and nighttime ambulatory BP, clock time-dependent methods are used when information on diary-based sleeping time is unavailable. The present study aimed to compare fixed-clock intervals with diary records to identify the associations of extreme dipper, dipper, non-dipper, and riser patterns with long-term cardiovascular risk among a general population. Design and method: Data were obtained from 1714 participants with no history of cardiovascular disease in Ohasama, Japan. We defined extreme dippers, dippers, non-dippers, and risers as nocturnal systolic BP decline > = 20%, 10–19%. 0–9%, and < 0%, respectively. We defined daytime and nighttime intervals as follows: 1) Diary cards, 2) standard fixed-clock (daytime, 09:00–21:00; nighttime, 01:00–06:00), 3) daytime 2h-early or 2h-late shifted fixed-clock (daytime, 07:00–19:00 or 11:00–23:00; nighttime, 01:00–06:00), 4) nighttime 2h-early or 2h-late shifted fixed-clock (daytime, 09:00–21:00; nighttime, 23:00–04:00 or 03:00–08:00). Cox regression analysis was used to estimate multivariable-adjusted hazard ratios (HRs). Results: Mean age was 60.6 years and 64.9% were women. Mean bedtime and wake-up time were 21:33 and 05:45, respectively. Over a mean follow-up period of 17.0 years, 206 cardiovascular deaths occurred. Based on diary records, HRs for cardiovascular death compared with dippers were 1.24 (95% confidence interval [CI], 0.82–1.87) in extreme dippers, 1.21 (0.87–1.69) in non-dippers, and the highest HR of 2.31 (1.47–3.62) was observed in risers. Using the standard fixed-clock interval, the daytime 2h-early shifted fixed-clock, the daytime 2h-late shifted fixed-clock, or the nighttime 2h-early shifted fixed-clock, the HR (95% CI) in risers compared with dippers was 1.57 (1.08–2.27), 1.57 (1.06–2.33), 1.44 (1.00–2.07), or 2.02 (1.33–3.05), respectively. Meanwhile, when dipping status was defined using the nighttime 2h-late shifted fixed-clock interval, the riser pattern was no longer significantly associated with the risk for cardiovascular death (HR compared with dippers, 1.29; 95% CI, 0.86–2.27). Conclusions: Although use of diary records remains preferable, the standard and nighttime 2h-early shifted fixed-clock intervals appear feasible for population-based studies.